There is at least one Airforce dealer in Canada
http://www.dlairgun.com/Air-Rifles/Airforce/ but in my opinion....PCP air rifles are really for the enthusiast. Lots of variables, lots of effort/time/$ to get set-up for re-fills. I've been tempted a few times, but for what you'd spend on all of that gear...you could get an awfully nice rimfire. Granted, not a .45 cal one.
I got as close as an air rifle that was fed by a 9oz. CO2 bottle and as much as I even liked that low-tech thing...seals/life-span of CO2 tanks, dropping pressure (=velocity) after a given # of shots. Seemed to always keep you guessing. PCP is more predictable than that, not nearly as temperature-sensitive...but more $ too.